twilight-gateway

twilight-gateway is an implementation of Discord's sharding gateway sessions. This is responsible for receiving stateful events in real-time from Discord and sending some stateful information.

It includes two primary types: the Shard and Cluster.

The Shard handles a single websocket connection and can manage up to 2500 guilds. If you manage a small bot in under about 2000 guilds, then this is what you use. See the Discord Docs/Sharding for more information on sharding.

The Cluster is an interface which manages the health of the shards it manages and proxies all of their events under one unified stream. This is useful to use if you have a large bot in over 1000 or 2000 guilds.

Examples

There are a few usage examples located in the root of the twilight repository.

Features

Deserialization

twilight-gateway supports serde_json and simd-json for deserializing and serializing events.

simd-json

The simd-json feature enables simd-json support to use simd features of modern cpus to deserialize responses faster. It is not enabled by default.

To use this feature you need to also add these lines to <project root>/.cargo/config:

[build]
rustflags = ["-C", "target-cpu=native"]

you can also use this environment variable RUSTFLAGS="-C target-cpu=native".

[dependencies]
twilight-gateway = { default-features = false, features = ["rustls-native-roots", "simd-json"], version = "0.2" }

TLS

Note: not enabling any TLS feature is support for use behind a proxy; Discord's API is HTTPS only.

twilight-gateway has features to enable tokio-tungstenite and twilight-http's TLS features. These features are mutually exclusive. rustls-native-roots is enabled by default.

native

The native feature enables tokio-tungstenite's native-tls feature as well as twilight-http's native feature which is mostly equivalent to using native-tls.

To enable native, do something like this in your Cargo.toml:

[dependencies]
twilight-gateway = { default-features = false, features = ["native"], version = "0.2" }

rustls-native-roots

The rustls-native-roots feature enables tokio-tungstenite's rustls-tls-native-roots feature and twilight-http's rustls-native-roots feature, which use rustls as the TLS backend and rustls-native-certs for root certificates.

This is enabled by default.

rustls-webpki-roots

The rustls-webpki-roots feature enables tokio-tungstenite's rustls-tls-webpki-roots feature and twilight-http's rustls-webpki-roots feature, which use rustls as the TLS backend and webpki-roots for root certificates.

This should be preferred over rustls-native-roots in Docker containers based on scratch.

zlib

zlib compression is enabled with one of the two zlib features described below.

There are 2 zlib features zlib-stock and zlib-simd, if both are enabled it will use zlib-simd.

zlib-stock is enabled by default.

Enabling zlib-simd will make the library use zlib-ng which is a modern fork of zlib that is faster and more efficient, but it needs cmake to compile.

Metrics

The metrics feature provides metrics information via the metrics crate. Some of the metrics logged are counters about received event counts and their types and gauges about the capacity and efficiency of the inflater of each shard.

This is disabled by default.